STM32F030R8. Need to get unitialized data from sram after standby, but the data are always initialized.
Hello,
I'm using STM32F030R8 Nucleo board to read unitialized data from sram (for sram puf purpose). I'm using Standby mode to repeatedly reset the board. It is woken up by RTC alarm. The problem is that the data I receive after reset are always initialized.
E.g. I set first byte of sram to value 2 and after return from Standby mode there is still value 2. I'm reading 64B from the beggining of sram, which is 0x20000000 (In .ld file I set the new beginning of sram to 0x20000040, so nothing would mess up the part of ram I'm reading). I use the PWR_EnterSTANDBYMode(), function provided with the ST-lib to enter Standby mode.
Anyone else that recognizes this behavior?
Thank you =)
int main(void)
{
/* Initialize serial communication */
initUart();
print("\r\nSerial init\r\n");
/* Initialize RTC modul */
StandbyRTCMode_Init();
/* Check and handle if the system was resumed from StandBy mode */
if (PWR_GetFlagStatus(PWR_FLAG_SB) != RESET)
{
/* Clear StandBy flag */
PWR_ClearFlag(PWR_FLAG_SB);
/* Check if the StandBy flag is cleared */
if (PWR_GetFlagStatus(PWR_FLAG_SB) != RESET)
{
while(1);
}
RTC_WaitForSynchro();
/* Read data from SRAM */
SRAMreadout();
/* Clear SRAM */
SRAMclear();
/* Enable Standby mode */
StandbyRTCMode_Measure();
}
else
{
/* Configure RTC modul */
StandbyRTCMode_Config();
/* Read data from SRAM */
initialSRAMreadout();
/* Clear SRAM */
SRAMclear();
/* Enable Standby mode */
StandbyRTCMode_Measure();
}
}
